Out of time

A friend of mine recently posted, "And poof!  Just like that, 1975 is fifty years ago."

My response was, "Sorry.  Wrong.  1975 is 25 years ago.  In five years, 1975 will still be 25 years ago.  That's my story, and I'm stickin' to it."

I've written here before about how plastic human memory is, but mostly I've focused on the content -- how we remember events.  But equally unreliable is how we remember time.  It's hard for me to fathom the fact that it's been six years since I retired from teaching.  On the other hand, the last overseas trip I took -- to Iceland, in 2022 -- seems like it was a great deal longer ago than that.  And 1975... well....  My own sense of temporal sequencing is, in fact, pretty faulty, and there have been times I've had to look up a time-stamped photograph, or some other certain reference point, to be sure when exactly some event had occurred.

Turns out, though, that just about all of us have inaccurate mental time-framing.  And the screw-up doesn't even necessarily work the way you'd think.  The assumption was -- and it makes some intuitive sense -- that memories of more recent events would be stronger than those from longer ago, and that's how your brain keeps track of when things happened.  It's analogous to driving at night, and judging the distance to a car by the brightness of its headlights; dimmer lights = the oncoming car is farther away.

But just as this sense can be confounded -- a car with super-bright halogen headlights might be farther away than it seems to be -- your brain's time sequencing can be muddled by the simple expedient of repetition.  Oddly, though, repetition has the unexpected effect of making an event seems like it happened further in the past than it actually did.

[Image licensed under the Creative Commons Isabelle Grosjean ZA, MontreGousset001, CC BY-SA 3.0]

A new study out of Ohio State University, published this week in the journal Psychological Science, shows that when presented with the same stimulus multiple times, the estimate of when the test subject saw it for the first time became skewed by as much as twenty-five percent.  It was a robust result -- holding across the majority of the hundreds of volunteers in the study -- and it came as a surprise to the researchers.

"We all know what it is like to be bombarded with the same headline day after day after day," said study co-author Sami Yousif.  "We wondered whether this constant repetition of information was distorting our mental timelines...  Images shown five times were remembered as having occurred even further back than those shown only two or three times.  This pattern persisted across all seven sets of image conditions...  We were surprised at how strong the effects were.  We had a hunch that repetition might distort temporal memory, but we did not expect these distortions to be so significant."

So when someone says "I know it happened that way, I remember it," it should be as suspect with respect to timing as it is to content.

"People should take away two things," Yousif said.  "(1) Time perception is illusory.  That is, our sense of when things occurred is systematically distorted in predictable ways.  (2) These distortions can be substantial, even if their causes are simple (i.e., the mere repetition of information)."

More and more it's seeming like what we think of as our rock-solid memory is an elaborate but rickety house of cards, composed of bits of accurate recollections mixed in with partial truths (real memories in the wrong sequence, or correctly sequenced memories that are being remembered imprecisely), along with a heaping helping of complete fiction.  Add to that the unsettling truth that unless you have a fixed, factual reference point, there's no way to tell the difference.

Makes you wonder how eyewitness testimony can still be used as the sine qua non of evidence in courts of law.

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Effect-before-cause

Astrophysicist Neil deGrasse Tyson said (apropos of UFO sightings), "The human brain and perceptual systems are rife with ways of getting it wrong."

It might be humbling, but it's nothing short of the plain truth, and doesn't just apply to seeing alien spaceships.  Especially in perfectly ordinary situations, we like to think that what we're hearing and seeing is an accurate reflection of what's actually out there, but the fact is we not only miss entirely a significant fraction of what we're experiencing, we misinterpret a good chunk of the rest.

Think you're immune?  Watch the following two-minute video, and see if you can figure out who killed Lord Smythe.

I don't know about you, but I didn't do so well.

It turns out that we don't just miss things that are there, we sometimes see things that aren't there.  Take, for example, the research that appeared last week in the journal Psychological Science, that suggests we make guesses about what we're going to see, and if those guesses don't line up with what actually happens, we "see" what we thought we were going to see rather than reality.

The experiment was simple enough.  It uses a short video of three squares (call them A, B, and C, from left to right).  Square A starts to move quickly to the right, and "collides" with B, which starts to move.  As you track it across the screen, it looks like B is going to collide with C, and repeat what happened in the previous collision.

The problem is, square C starts to move not only before B hits it, but before B itself starts moving.  In other words, there is no way a collision with B could have been what triggered C to start moving.  But when test subjects were asked what order the squares started moving, just about everyone said A, then B, then C.  Our expectation of cause-and-effect are so strong that even on multiple viewings, test subjects still didn't see C begin to move before B.

"We have a strong assumption that we know, through direct perception, the order in which events happen around us," said study co-author Christos Bechlivanidis, of University College London.  "The order of events in the world is the order of our perceptions.  The visual signal of the glass shattering follows the signal of the glass hitting the ground, and that is taken as irrefutable evidence that this is indeed how the events occurred.  Our research points to the opposite direction, namely, that it is causal perceptions or expectations that tell us in what order things happen.  If I believe that the impact is necessary for the glass to break, I perceive the shattering after the impact, even if due to some crazy coincidence, the events followed a different order.  In other words, it appears that, especially in short timescales, it is causation that tells us the time."

As I and many others have pointed out about previous research into what is now known as "inattentional blindness," this is yet another nail in the coffin of eyewitness testimony as the gold standard of evidence in the court of law.  We still rely on "I saw it with my own eyes!" as the touchstone for the truth, even though experiment after experiment has shown how unreliable our sensory-perceptive systems are.  Add to that how plastic our memories are, and it's a travesty that people's fates are decided by juries based upon eyewitness accounts of what happened, sometimes in the distant past.

[Image licensed under the Creative Commons Eric Chan from Palo Alto, United States, Mock trial closing, CC BY 2.0]

To end with another quote by NdGT -- "There's no such thing as good eyewitness testimony and bad eyewitness testimony.  It's all bad."

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